Endocranial endoscopes are surveyed in Gaab M R, Instrumentation: Endoscopes and Equipment, World Neurosurgery 79[2s]: S14.E1-S14.E21, February 2013. Another example of intracranial endoscopes is discussed in Schroeder H W S, A New Multipurpose Ventriculoscope, Neurosurgery, Vol. 62, Number 2, February 2008, 489-492. Other examples of endoscopes are discussed in US 1010/0022824 A1, WO 2013/082497 A1, US 2012/0330196 A1, US 2009/0054733 A1, 2009/0198216 A1, WO 2010/126586 A1, US 2004/0167542, US 2008/0154181 A1, and US 2014/0148727 A1.